My yorkie does exactly the same during the warm weather - I took him to the vet because I thought it may be excema but she said its an allergy similar to hayfever to humans but dogs get itchy skin and the back end near their tail is the easiest place for them to scratch so they end up with broken excema like skin - Toby is now on piriton from the vet and I came on this site today to ask if piriton you can buy over the counter in the chemist is the same - would it be safe to use? Hope your dog is ok, mine seems to be getting better now piriton is working. xx